{"id":"CVE-2026-100635","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-100635","generatedAt":"2026-10-28T03:32:13.129Z","title":"SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections.","description":"SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections. An on-path attacker can observe a valid publish-visitor-session-id cookie from a Basic Auth exchange and replay it to access authenticated publish endpoints without knowing the account password.","published":"2026-09-26T14:16:45.000Z","lastModified":"2026-10-08T16:16:58.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":8.2,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-319"],"affected":[],"epss":{"score":0.00327,"percentile":0.25659,"date":"2026-10-27","history":[{"date":"2026-09-27","score":0.00259,"percentile":0.15772}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-26T14:16:45.000Z","detail":{"score":"8.2","severity":"HIGH","publishedAt":"2026-09-26T14:16:45.007Z"},"summary":"New CVE, high severity (CVSS 8.2)."}],"references":[{"url":"https://github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682","source":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/commit/ff4d215f78a8d6e6db6052be18b5f9f4db9c7d68","source":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/siyuan-before-3.8.4-authentication-bypass-via-plaintext-session-cookie","source":"disclosure@vulncheck.com"},{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7j37-4gq6-wm7m","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-100635","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}